Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L15/00—Compositions of rubber derivatives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
  • C08C19/00—Chemical modification of rubber
  • C08C19/30—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule
  • C08C19/42—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with metals or metal-containing groups
  • C08C19/44—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with metals or metal-containing groups of polymers containing metal atoms exclusively at one or both ends of the skeleton
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L21/00—Compositions of unspecified rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/002—Physical properties
  • C08K2201/006—Additives being defined by their surface area
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L7/00—Compositions of natural rubber
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
  • Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction 

Definitions

• the present invention relates to a rubber composition based on one or more functionalized diene elastomers and one or more carbon blacks with a specific CTAB surface area, as well as a semi-finished article comprising it, and a tire incorporating such a semi-finished article.
• a rubber composition based on one or more functionalized diene elastomers and one or more surface-specific carbon blacks CTAB (measured according to the standard NFT 45-007, November 1987, method B) ranging from 100 to 200 m 2 / g, said functionalized diene elastomer (s) being composed of a particular diene elastomer functionalized at the chain end or in the middle of the chain by a tin function, and of a content of less than 15% by weight relative to the total weight of the functionalized diene elastomer of a particular non-functional tin elastomer, allowed to achieve these objectives.
• CTAB surface-specific carbon blacks
• the functionalized diene elastomer according to the invention comprises from 5% to 45% by weight, preferably from 10% to 30% by weight relative to the total weight of the functionalized diene elastomer of said tin stellate elastomer c).
• the functionalized diene elastomer according to the invention comprises a level strictly greater than 0% by weight and less than 10% by weight, and more preferentially a lower rate than 5% by weight relative to the total weight of the functionalized diene elastomer of said non-functional tin elastomer b).
• composition based on is meant a composition comprising the mixture and / or the reaction product of the various constituents used, some of these basic constituents being capable of or intended to react with one another, at least partly, during the various phases of manufacture of the composition, in particular during its vulcanization.
• the term "functionalized diene elastomer” is understood to mean a diene elastomer which comprises a group comprising one or more heteroatoms.
• This grouping can be at the end of the chain. It will then be said that the diene elastomer is functionalized at the end of the chain or at the end of the chain.
• This is generally an elastomer obtained by reacting a living elastomer with a functionalizing agent, that is to say any molecule that is at least monofunctional, the function being any type of chemical group known to those skilled in the art for reacting with a piece of living chain.
• This grouping can be in the linear main elastomeric chain. It will be said that the diene elastomer is coupled or functionalized in the middle of the chain, as opposed to the position "at the end of the chain” and although the group is not precisely in the middle of the elastomeric chain. It is generally an elastomer obtained by reaction of a living elastomer on a coupling agent, that is to say any molecule at least difunctional, the function being any type of chemical group known to those skilled in the art to react. with a piece of living chain.
• This group can be central to which n chains or elastomer branches (n> 2) are linked forming a star structure of the elastomer. It will then be said that the diene elastomer is starred with n branches. It is generally an elastomer obtained by reaction of a living elastomer on a starzing agent, that is to say any multifunctional molecule, the function being any type of chemical group known to those skilled in the art to react with a piece of living chain.
• polydispersity index is meant in the sense of the invention the ratio weight average molecular weight / number average molecular weight. The minimum theoretical value being 1.
• the diene elastomer a) is functionalized at the end or in the middle of the chain by a tin function.
• the functionalization may be obtained with a mono- halo-tin or di-halo - tin functionalization agent which may correspond to the general formula R 4-x SnX 0 x , where x represents an integer of value 1 or 2, R represents an alkyl radical, cycloalkyl, aryl, alkaryl or vinyl having 1 to 12 carbon atoms, preferably butyl, and X 0 is a halogen atom, preferably chlorine.
• R 4-x SnX 0 x R 4-x SnX 0 x
• R represents an alkyl radical, cycloalkyl, aryl, alkaryl or vinyl having 1 to 12 carbon atoms, preferably butyl
• X 0 is a halogen atom, preferably chlorine.
• the functionalization can be obtained with a functionalising agent derived from tin that can respond to the general formula (X 1 y R 1 3-y Sn) -O- (SnR 1 3 -z X 1 z ) or (X 1 y R 1 3-y Sn) -O- (CH 2 ) e -O- (SnR 1 3 -z X 1 z ), where y and z represent integers between 0 and 2 and y + z equal to 1 or 2, R 1 represents an alkyl, cycloalkyl, aryl, alkaryl or vinyl radical having 1 to 12 carbon atoms, preferably butyl, X 1 is a halogen atom, preferably chlorine, and e represents an integer of 1 to 20, preferably 4.
• Starring may be obtained with a tri or tetrahalogenotin starring agent which may correspond to the general formula R 2 q SnX 2 4-q , where q represents an integer of value 0 or 1, R 2 represents an alkyl radical, cycloalkyl, aryl, alkaryl or vinyl having 1 to 12 carbon atoms, preferably butyl, and X 2 is a halogen atom, preferably chlorine.
• a preferred starch agent mention may be made of butyl tin trichloride or tin tetrachloride.
• the starring can be obtained with a functionalization agent derived from tin that can meet the general formula (X 3 k R 3 3 -k Sn) -O- (SnR 3 3-1 X 3 1 ) or (X 3 k R 3 3 -k Sn) -O- (CH 2) f -O- (SnR 3 3-1 X 3 1 ), where k and 1 represent integers between 0 and 3, k + 1 integers between 3 and 6, R 3 represents a radical alkyl, cycloalkyl, aryl, alkaryl or vinyl having from 1 to 12 carbon atoms, preferably butyl, X 3 is a halogen atom, preferably chlorine and f represents an integer of value from 1 to 20 preferably 4 .
• the diene elastomer a) is a diene elastomer functionalized with a tin function in the middle of the chain.
• the diene elastomer c) is a tin diene elastomer with 4 branches.
• the diene elastomer a) is a diene elastomer functionalized with a tin function in the middle of the chain and the diene elastomer c) is a dotted tin diene elastomer with 4 branches.
• the diene elastomer b) is non-functional tin. Said elastomer can be obtained during functionalization.
• the diene elastomer a) functionalised at the chain end or in the middle of the chain by a tin function has a monomodal molecular weight distribution before functionalization and a polydispersity index before functionalization less than 1, 3.
• the diene diene elastomer c when present, has a monomodal molecular weight distribution before staring and a polydispersity index before staring less than 1.3.
• diene elastomer is meant according to the invention any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 12 carbon atoms, or any block copolymer, random, sequential or microsequenced, obtained by copolymerization of one or more dienes conjugated with each other or with one or more vinylaromatic compounds having 8 to 20 carbon atoms.
• copolymers these contain from 20% to 99% by weight of diene units, and from 1 to 80% by weight of vinylaromatic units.
• Conjugated diene monomers which can be used in the process according to the invention are especially suitable for 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3 di (C 1 -C 5 alkyl) -1,3-butadiene, such as for example 2,3-dimethyl-1,3-butadiene, 2,3 1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene, 3-pentadiene, 2,4-hexadiene.
• vinylaromatic compounds are especially suitable styrene, ortho-, meta, para-methylstyrene, the commercial mixture "vinyltoluene", para-tert-butylstyrene, methoxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, etc.
• the diene elastomer is chosen from polybutadienes, random copolymers or butadiene-styrene block, random copolymers or butadiene-isoprene block, random copolymers or butadiene-styrene-isoprene block, statistical copolymers or styrene-block copolymers. isoprene and synthetic polyisoprene.
• polybutadienes and in particular those having a content (mol%) in units -1.2 of between 4% and 80% polyisoprenes, butadiene-styrene copolymers and in particular those having a Tg (temperature of glass transition (Tg, measured according to ASTM D3418) between 0 ° C. and -70 ° C. and more particularly between -10 ° C. and -60 ° C., a styrene content of between 5% and 60% by weight and more particularly between 20% and 50%, a content (mol%) in -1,2 bonds of the butadiene part of between 4% and 75%, a content (mol%) of trans-1,4 bonds of between 10% and 80%.
• Tg temperature of glass transition
• copolymers of b utadiene-styrene-isoprene are especially suitable those having a styrene content of between 5% and 50% by weight and more particularly between 10% and 40%, an isoprene content of between 15% and 60% by weight and more particularly between 20% and 50%, a butadiene of between 5% and 50% by weight and more particularly between 20% and 40%, a content (mol%) in -1,2 units of the butadiene part of between 4% and 85%, a content (mol% ) in trans-1,4 units of the butadiene part of between 6% and 80%, a content (mol%) in -1,2 units plus -3,4 of the isoprenic part of between 5% and 70% and a content (mol%) in trans-1,4 units of the isoprene part of between 10% and 50%, and more generally any butadiene-styrene-isoprene copolymer having a Tg of between -5 ° C and -
• the ratio of the number average molecular weight Mn1 of each end-B polybutadiene or polyisoprene block to the number-average molecular weight Mn2 of each of the C blocks varies from 5 to 20%.
• the block or blocks C are chosen from copolymers of styrene and butadiene, copolymers of styrene and isoprene, copolymers of butadiene and isoprene, copolymers of styrene / butadiene / isoprene, polyisoprene when the neighboring B block is a polybutadiene, and the polybutadiene when the neighboring B block is a polyisoprene.
• the block or blocks C are chosen from copolymers of styrene and butadiene.
• B is polyisoprene
• C is a copolymer of styrene and butadiene
• the block copolymer a) being functionalized with the dibutyltin dichloride functionalizing agent (Bu 2 SnCl 2 ) and the block copolymer c) being starred by the star-tetrachloride stain agent (SnCl 4 ).
• B is polybutadiene
• C is a copolymer of styrene and butadiene
• the block copolymer a) being functionalized with the functionalizing agent dibutyltin dichloride (Bu 2 SnCl 2 ) and the block copolymer c) being starred by the tin tetrachloride staring agent (SnCl 4 ).
• the diene elastomer a) may comprise an amine function at one or all ends of the non-functionalized tin chain.
• the optionally present diene elastomer c) may comprise an amine function at the ends of the non-starred tin chains.
• the non-functional tin diene elastomer b) may comprise an amine function at one end of the chain.
• the polymerization of diene monomers is initiated by an initiator.
• an initiator any known monofunctional anionic initiator can be used.
• an initiator containing an alkali metal such as lithium is used preferentially.
• Suitable organolithium initiators include those having a carbon-lithium bond. Preferably, use will be made of an organolithium hydrocarbon initiator having no heteroatom. Representative compounds are aliphatic organoliths such as ethyllithium, n-butyllithium (n-BuLi), isobutyl lithium.
• organolithium compounds comprising a nitrogen-lithium bond
• R 1 and R 2 denote an alkyl, cycloalkyl or aryl radical containing from 1 to 20 carbon atoms
• R 3 a radical cyclic alkyl, branched or unbranched, containing from 3 to 16 carbon atoms
• R 4 an alkyl, cycloalkyl or aryl radical containing from 1 to 20 carbon atoms
• the polymerization is, as known per se, preferably carried out in the presence of an inert solvent which may be for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane or an aromatic hydrocarbon such as benzene, toluene, xylene.
• an inert solvent which may be for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane or an aromatic hydrocarbon such as benzene, toluene, xylene.
• the polymerization can be carried out continuously or discontinuously, preferably batchwise.
• the polymerization is generally carried out at a temperature of between 20 ° C. and 120 ° C. and preferably in the region of 30 ° C. to 90 ° C. It is of course also possible to add at the end of the polymerization a transmetallation agent for modifying the reactivity of the living-chain end.
• the living diene elastomer resulting from the polymerization is then functionalized to prepare the functionalized diene elastomer according to the invention.
• the polymerization of diene monomers, isoprene or butadiene is initiated by said organolithium initiators in order to obtain a living polyisoprene or polybutadiene diene homopolymer.
• the living diene homopolymer thus obtained is then used as an initiator (initiator) for the preparation of the diene elastomer to obtain a living block copolymer.
• initiator initiator
• the discerning reader would understand that during the second stage of preparation, adequate working conditions must be put in place in order to limit the formation of dead or deactivated polyisoprene or polybutadiene diene homopolymer thus generating low molecular weight chains. An amount greater than 1% by weight of these polyisoprene or polybutadiene chains could penalize the properties of the functionalized diene elastomer according to the invention.
• the living block copolymer resulting from the polymerization is then functionalized to prepare the functionalized diene elastomer according to the invention.
• the functionalized diene elastomer a) and the optional diene diene elastomer c) are mixed in the proportions necessary to minimize the level of diene elastomer.
• the functionalized diene elastomer a) can be obtained in a manner known per se by reaction of a tin derivative with the living diene elastomer resulting from the polymerization.
• the optional stellate elastomer c) can be obtained in a manner known per se by reacting a tin-containing starring agent on the living diene elastomer resulting from the polymerization.
• the two elastomers can be mixed in an inert solvent, for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane or an aromatic hydrocarbon such as benzene, toluene, xylene, which may be the same as the polymerization solvent.
• an inert solvent for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane or an aromatic hydrocarbon such as benzene, toluene, xylene, which may be the same as the polymerization solvent.
• the mixing is then carried out at a temperature of preferably between 20 ° C and 120 ° C, preferably in the region of 30 ° C to 90 ° C.
• the living diene elastomer resulting from the polymerization stage is subjected to the reaction of a starter agent and that of a functionalizing agent.
• the functionalization of the living diene elastomer resulting from the polymerization step can be carried out at a temperature ranging from 30 to 120 ° C., in the presence initially of an appropriate amount of an agent starring to starter preferably from 5 to 45% by weight of the living elastomer.
• the remaining living chains of the diene elastomer obtained after the first step are functionalized by adding a functionalization agent to tin, which can introduce at the end of the chain or in the middle of the chain a tin function.
• the functionalization reaction of the diene elastomer is then stopped by the deactivation of the remaining living chains.
• the functionalized diene elastomer (s) generally represent from 30 to 100 phr of the composition.
• the composition according to the invention comprises, as a majority filler, one or more carbon blacks with a CTAB specific surface area ranging from 100 to 200 m 2 / g, preferably from 120 to 180 m 2 / g.
• the specific surface CTAB is determined according to the standard NFT 45-007 (November 1987, method B).
• Suitable carbon blacks are all carbon blacks, especially blacks of the HAF, ISAF, SAF type conventionally used in tires (so-called pneumatic grade blacks) whose CTAB specific surface area (determined according to the French standard NF T 45-007). November 1987, method B) greater than or equal to 100 m 2 / g, which corresponds in particular to reinforcing carbon blacks such as "CRX1346" or blacks of series 100, 200 (ASTM grades), for example the N115, N134, N220 and N234. More preferably, the carbon blacks will have a specific surface area of at least 100 m 2 / g and at most 200 m 2 / g, particularly at least 120 m 2 / g and at most 180 m 2 / g. .
• the carbon black (s) with a specific surface area CTAB ranging from 100 to 200 m 2 / g generally represent at least 30 and at most 130 phr, preferably at most 100 phr. Preferably, this level is in a range from 30 to 90 phr, preferably from 30 to 70 phr, more preferably from 40 to 60 phr.
• composition according to the invention may also comprise, as non-majority filler, one or more other reinforcing fillers different from carbon blacks with a CTAB specific surface area varying from 100 to 200 m 2 / g.
• reinforcing filler Any type of reinforcing filler known for its ability to reinforce a rubber composition that can be used for manufacturing tires, for example a reinforcing organic filler such as carbon black with a CTAB specific surface area of less than 100, may be used as a non-majority filler.
• a reinforcing organic filler such as carbon black with a CTAB specific surface area of less than 100, may be used as a non-majority filler.
• blacks of higher series FF, FEF, GPF, SRF for example blacks N660, N683, N772.
• the carbon blacks could for example already be incorporated into the isoprene elastomer in the form of a masterbatch (see for example applications WO 97/36724 or WO 99/16600 ).
• reinforcing filler may be used in blending with carbon black, in particular other reinforcing organic fillers or reinforcing inorganic fillers.
• organic fillers other than carbon blacks
• any inorganic or mineral filler (regardless of its color and origin (natural or synthetic), also called “white” filler, “clear” filler or “non-black filler” as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires, in other words, able to replace, in its reinforcing function, a conventional carbon black of pneumatic grade, such a charge is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) on its surface.
• -OH hydroxyl groups
• the physical state in which the reinforcing inorganic filler is present is indifferent whether in the form of powder, microbeads, granules, beads or any other suitable densified form.
• the term "reinforcing inorganic filler” also refers to mixtures of different inorganic fillers. reinforcing agents, in particular highly dispersible siliceous and / or aluminous fillers as described below.
• Suitable reinforcing inorganic fillers are, in particular, mineral fillers of the siliceous type, in particular silica (SiO 2 ), or of the aluminous type, in particular alumina (Al 2 O 3 ).
• the silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface and a CTAB specific surface both less than 450 m 2 / g, preferably from 30 to 400 m 2 / g.
• HDS highly dispersible precipitated silicas
• the Ultrasil 7000 and Ultrasil 7005 silicas from Degussa the Zeosil 1165MP, 1135MP and 1115MP silicas from Rhodia
• the Hi-Sil EZ150G silica from the company PPG
• the silicas Zeopol 8715, 8745 and 8755 of the Huber Company the silicas with high specific surface as described in the application WO 03/16837 .
• an at least bifunctional coupling agent intended to ensure a sufficient chemical and / or physical connection between the inorganic filler (surface of its particles) and the diene elastomer, in particular organosilanes or bifunctional polyorganosiloxanes.
• Polysulphurized silanes called “symmetrical” or “asymmetrical” silanes according to their particular structure, are used, as described, for example, in the applications WO03 / 002648 (or US 2005/016651 ) and WO03 / 002649 (or US 2005/016650 ).
• polysulphurized silanes mention may be made more particularly of polysulfides (especially disulfides, trisulphides or tetrasulfides) of bis- (C 1 -C 4 alkoxyl) -alkyl (C 1 -C 4 ) silyl-alkyl (C 1 -C 4 )), such as, for example, bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl) polysulfides.
• polysulfides especially disulfides, trisulphides or tetrasulfides of bis- (C 1 -C 4 alkoxyl) -alkyl (C 1 -C 4 ) silyl-alkyl (C 1 -C 4 )
• bis- (C 1 -C 4 alkoxyl) -alkyl (C 1 -C 4 ) silyl-alkyl (C 1 -C 4 ) such as, for example, bis (3-
• TESPT bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis-disulfide ( triethoxysilylpropyl)
• polysulfides especially disulphides, trisulphides or tetrasulfides
• bis- (monoalkoxyl (C 1 -C 4 ) -dialkyl (C 1 -C 4 ) silylpropyl) more particularly bis-monoethoxydimethylsilylpropyl tetrasulfide as described in the application for patent WO 02/083782 (or US 2004/132880 ).
• POS polyorganosiloxanes
• the content of coupling agent is preferably between 0.3 and 12 phr, more preferably between 0.5 and 3 phr or between 3 and 8 phr. But it is generally desirable to use as little as possible.
• the level of coupling agent typically represents at least 0.5% and at most 15%, or even at most 12%, by weight relative to the amount of inorganic filler.
• the filler content in the composition is at least 30 phr, more preferably at least 50 phr, and at most 150 phr, more preferably at most 120 phr.
• the optimum is different depending on the specific applications targeted.
• the person skilled in the art also knows how to adapt the total rate of total reinforcing filler (carbon black and reinforcing inorganic filler such as silica), depending on the specific surface area of this total rate and on the other hand the rolling resistance, wet wear and wet performance values which must be attained for the considered pneumatic.
• composition according to the invention may also comprise at least one diene elastomer different from said functionalized diene elastomer according to the invention.
• diene elastomers different from the functionalized diene elastomer according to the invention may be chosen from diene elastomers conventionally used in tires, such as natural rubber or a synthetic elastomer, or another functionalized or star-shaped elastomer.
• composition according to the invention may also comprise a chemical crosslinking agent.
• Chemical crosslinking allows the formation of covalent bonds between the elastomer chains.
• the chemical crosslinking can be done by means of a vulcanization system or by means of peroxide compounds.
• the vulcanization system itself is based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator.
• sulfur or a sulfur-donor agent
• a primary vulcanization accelerator To this basic vulcanization system are added, incorporated during the first non-productive phase and / or during the production phase as described later, various known secondary accelerators or vulcanization activators such as zinc oxide.
• Sulfur is used at a preferential rate of between 0.5 and 12 phr, in particular between 1 and 10 phr.
• the primary vulcanization accelerator is used at a preferred level of between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.
• Any compound that can act as a vulcanization accelerator can be used as an accelerator (primary or secondary) diene elastomers in the presence of sulfur, in particular thiazole type accelerators and their derivatives, accelerators of the thiuram type, zinc dithiocarbamates.
• accelerators are for example selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS”), tetrabenzylthiuram disulfide (“TBZTD”), N-cyclohexyl-2-benzothiazyl sulfenamide (“CBS”), N, N dicyclohexyl-2-benzothiazyl sulphenamide (“DCBS”), N-tert-butyl-2-benzothiazyl sulphenamide (“TBBS”), N-tert-butyl-2-benzothiazyl sulphenimide (“TBSI”), zinc dibenzyldithiocarbamate (“ ZBEC ”) and mixtures of these compounds.
• MBTS 2-mercaptobenzothiazyl disulfide
• TBZTD tetrabenzylthiuram disulfide
• CBS N-cyclohexyl-2-benzothiazyl sulfen
• a primary accelerator of the sulfenamide type is used.
• the peroxide compound (s) represent (s) from 0.01 to 10 phr.
• acyl peroxides for example benzoyl peroxide or p-chlorobenzoyl peroxide
• peroxide ketones for example methyl ethyl ketone peroxide or peroxyesters
• alkyl peroxides for example dicumyl peroxide, di-t-butyl peroxybenzoate and 1,3-bis (t-butyl peroxyisopropyl) benzene
• hydroperoxides for example t-butyl hydroperoxide.
• the rubber composition according to the invention may also comprise all or part of the usual additives normally used in elastomer compositions intended for the manufacture of tires, in particular treads, for example plasticizers or extension oils. , whether the latter are of aromatic or non-aromatic nature, pigments, protective agents such as anti-ozone waxes (such as C32 ST Ozone wax), chemical antiozonants, anti-oxidants (such as the paraphenylenediamine), anti-fatigue agents, reinforcing resins, acceptors (for example phenolic resin novolak) or methylene donors (for example HMT or H3M) as described for example in the application WO 02/10269 adhesion promoters (cobalt salts for example).
• additives normally used in elastomer compositions intended for the manufacture of tires, in particular treads for example plasticizers or extension oils.
• plasticizers or extension oils for example plasticizers or extension oils.
• protective agents such as anti-ozone waxes (such as C32 ST Ozone wax
• the composition according to the invention comprises, as preferential non-aromatic or very weakly aromatic plasticizing agent, at least one compound chosen from the group consisting of naphthenic, paraffinic, MES, TDAE and ester oils (in particular glycerol trioleates), the hydrocarbon plasticizing resins having a high Tg preferably greater than 30 ° C, and mixtures of such compounds.
• at least one compound chosen from the group consisting of naphthenic, paraffinic, MES, TDAE and ester oils (in particular glycerol trioleates) the hydrocarbon plasticizing resins having a high Tg preferably greater than 30 ° C, and mixtures of such compounds.
• composition according to the invention may also contain, in addition to the coupling agents, activators for coupling the reinforcing inorganic filler or, more generally, processing aid agents that are capable in a known manner, thanks to an improvement in the dispersion of the inorganic filler in the rubber matrix and a lowering of the viscosity of the compositions, to improve their ability to use in the green state, these agents being, for example, hydrolysable silanes such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycols), primary, secondary or tertiary amines (for example trialkanol amines), hydroxylated or hydrolyzable POSs, for example ⁇ , ⁇ -dihydroxy-polyorganosiloxanes (especially ⁇ , ⁇ -dihydroxy-polydimethylsiloxanes), fatty acids such as, for example, stearic acid.
• composition according to the invention is manufactured in a suitable mixer, using two successive preparation phases well known to those skilled in the art: a first phase of work or thermomechanical mixing (sometimes referred to as a "non-productive" phase at high temperature, up to a maximum temperature (denoted Tmax) of between 100 ° C. and 190 ° C., preferably between 130 ° C.
• a first phase of work or thermomechanical mixing sometimes referred to as a "non-productive" phase at high temperature, up to a maximum temperature (denoted Tmax) of between 100 ° C. and 190 ° C., preferably between 130 ° C.
• a second mechanical working phase (sometimes referred to as a "productive" phase )
• a second mechanical working phase (sometimes referred to as a "productive" phase)
• a lower temperature typically below 110 ° C, for example between 60 ° C and 100 ° C, finishing phase during which the chemical crosslinking agent is incorporated; such phases have been described in the EP-A-0501227 , EP-A-0735088 , EP-A-0810258 , WO00 / 05300 or WO00 / 05301 .
• the first (non-productive) phase is preferably carried out in two thermomechanical steps.
• all the necessary basic constituents with the exception of the chemical crosslinking agent, are introduced into a suitable mixer such as a conventional internal mixer.
• This first step is carried out at a temperature between 110 ° C and 190 ° C and preferably between 130 ° C and 180 ° C.
• the total mixing time is preferably between 2 and 5 minutes.
• the chemical crosslinking agent is then incorporated at low temperature, generally in an external mixer such as a roll mill; the whole is then mixed (productive phase) for a few minutes, for example between 5 and 15 minutes.
• the final composition thus obtained is then calendered, for example in the form of a sheet or a plate, in particular for a characterization in the laboratory, or extruded, to form for example a rubber profile used for the manufacture of semi-finished products. finished such as treads.
• the vulcanization (or cooking) is conducted in a known manner at a temperature generally between 130 ° C and 200 ° C, under pressure, for a sufficient time which may vary for example between 5 and 90 minutes depending in particular on the cooking temperature , the vulcanization system adopted, the kinetics of vulcanization of the composition in question or the size of the tire.
• the subject of the invention is also a semi-finished article made of rubber for a tire, comprising the rubber composition according to the invention.
• said article is a tread.
• the invention finally relates to a tire comprising a semi-finished article according to the invention.
• the purpose of this example is to compare the processing properties and the dynamic properties of different rubber compositions, as well as the pneumatic tire performance obtained from these rubber compositions.
• the composition A0 is a control composition.
• compositions A2 and A5 are comparative compositions.
• compositions A1, A3, A4, A6 and A7 are compositions according to the invention.
• the carbon black content has been adapted so that they have the same rigidity G * 50% peak-to-peak (dynamic property in shear) as measured according to the ASTM standard D2231-71.
• the molecular weight Mn of this polymer, determined by the SEC technique, is 145,000 g.mol -1 , the Ip is 1.7.
• (3) tin-coupled SBR with a low polydispersity index, according to the invention: styrene-butadiene copolymer with the following mass ratios: 45.0% of 1,4-trans BR; 30.3% 1,4-cis BR; 24.8% of BR 1,2; 28.2% styrene (Tg -49 ° C).
• the molecular weight Mn of this polymer, determined by the SEC technique, is 178,900 g.mol -1 , the Ip is 1.25.
• the PI / SBIR ratio is 10.5%.
• the molecular weight Mn of this polymer, determined by the SEC technique, is 169,000 g.mol -1 , the Ip is 1.26.
• N-1,3-dimethylbutyl N-phenylparaphenylenediamine (6-PPD) (6) N-cyclohexyl-2-benzothiazylsulfenamide (CBS)
• the rubber compositions are characterized by the following measurements.
• Mooney viscosity ML (1 + 4) at 100 ° C is measured according to ASTM standard D-1646.
• the dynamic properties ⁇ G * and tan ( ⁇ ) max are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard.
• the response of a sample of vulcanized composition (cylindrical specimen 2 mm thick and section 79 mm 2 ), subjected to sinusoidal stress in alternating simple shear, at the frequency of 10 Hz, under normal conditions is recorded. temperature (60 ° C) according to ASTM D 1349-99.
• a peak-to-peak deformation amplitude sweep is performed from 0.1% to 100% (forward cycle) and then from 100% to 0.1% (return cycle).
• the results exploited are the complex dynamic shear modulus (G *) and the loss factor tan ⁇ .
• the hysteresis (tan ⁇ max) is expressed by the delta tan measurement at 7% deformation according to the ASTM D2231-71 standard.
• the treads were made from the rubber compositions summarized in Table 1, according to the method detailed in the description.
• the wear tests were carried out for tires of dimensions 315 / 70R22.5 XZE2 mounted on the front position of a tractor-type truck.
• the wear roll is conducted over a distance of 60,000 km.
• the wear performance expressed in base 100 of the control is calculated by the ratio between the average height loss measured for the two tires of the control composition A0 and the average height loss for the two tires of the composition An (0 ⁇ n ⁇ 7 ).
• the rolling resistance measurement is performed according to ISO 9948, applicable to light truck and truck tires.
• the tire is rolled on a large diameter flywheel driven by a motor.
• the method consists in measuring the deceleration of the system at around 80 km / h to deduce the rolling resistance.
• the rolling resistance expressed in base 100 of the control is expressed as the ratio between the rolling resistance force of the control tire consisting of the composition A0 and the rolling resistance force of the tire consisting of the composition An (1 ⁇ n ⁇ 7 ).
• the rolling resistance force is deduced from the measured overall braking force at which the free-wheel slowing force and the retarding force of the freewheel are subtracted.
• compositions A0 and A1 demonstrates the known fact that the use of a low polydispersity index SBR instead of a high polydispersity index SBR improves the implementation (reduction of the Mooney plasticity). , rolling resistance, without penalizing wear.
• composition A0, A2 and A5 highlights the known fact that the increase in the specific surface area of the carbon blacks improves the wear resistance of the tires but is accompanied by an increase in the Mooney plasticity and an unacceptable penalty for rolling resistance (A2 and A5).
• compositions A3, A4, A6 and A7 according to the invention exhibit significant improvement in wear, rolling resistance (A3, A4 and A7), without penalizing the implementation (Mooney plasticity), in comparison with the performance of the composition of the control A0.

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• Chemical & Material Sciences (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
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• 2010
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